A crosspiece for a motor vehicle dashboard is already known that extends substantially in a longitudinal direction and comprises:                a first portion of the crosspiece, made of a first material, the first portion of the crosspiece extending substantially in the longitudinal direction and having a closed cross-section perpendicular to the longitudinal direction, the first portion of the crosspiece comprising a hollow joining end,        a second portion of the crosspiece, made of a second material, the first material being different from the second material.        
The use of two different materials to create a vehicle crosspiece may in particular allow reducing the weight.
Document DE102011101581 discloses an example of a crosspiece comprising a first portion made of a first material and a second portion made of a second material, the first and second materials being different. The first and second portions are connected to one another by means of a connector fitted on the one hand into the first portion and on the other hand into the second portion. This connector is force-fitted into the first portion to secure it, or is secured by riveting. This connector is also fitted into the second portion, and a weld bead is provided to secure the second portion and the connector. The assembly of the first and second portions is thus achieved by means of a third part. This third part results in a more complicated manufacturing process. In addition, the attachment provided by this third part may not be sufficiently strong or robust, depending on the types of materials used for the first and second portions, which may pose safety issues. Therefore, for the purposes of creating a crosspiece that is not too heavy while retaining attractive mechanical properties of rigidity and robustness without complicating the industrial process, the present invention aims to improve the prior art.